Add workaround for errata 790748 for Cortex-A75

Internal timing conditions might cause the CPU to stop processing
interrupts. Set bit 13 of CPUACTLR_EL1 to prevent this.

Change-Id: Ifdd19dbcdb71bb0d9609cab1315c478aaedb03ba
Signed-off-by: Louis Mayencourt <louis.mayencourt@arm.com>
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index be7d3bd..a7acd2f 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -127,6 +127,10 @@
 # only to revision <= r0p0 of the Cortex A75 cpu.
 ERRATA_A75_764081	?=0
 
+# Flag to apply erratum 790748 workaround during reset. This erratum applies
+# only to revision <= r0p0 of the Cortex A75 cpu.
+ERRATA_A75_790748	?=0
+
 # Flag to apply T32 CLREX workaround during reset. This erratum applies
 # only to r0p0 and r1p0 of the Neoverse N1 cpu.
 ERRATA_N1_1043202	?=1
@@ -204,6 +208,10 @@
 $(eval $(call assert_boolean,ERRATA_A75_764081))
 $(eval $(call add_define,ERRATA_A75_764081))
 
+# Process ERRATA_A75_790748 flag
+$(eval $(call assert_boolean,ERRATA_A75_790748))
+$(eval $(call add_define,ERRATA_A75_790748))
+
 # Process ERRATA_N1_1043202 flag
 $(eval $(call assert_boolean,ERRATA_N1_1043202))
 $(eval $(call add_define,ERRATA_N1_1043202))